An interesting file is available from site marksrussianmilitaryhistory. It is a report of the Soviet 10th Tank division, detailing the operations of the unit during June and July ’41.
Comment: If we take the ratio of faults per vehicle then only the KV has a ratio of over 1, the rest of the vehicles are below 1. Alternatively one can say that 24% of the T-34’s and 35% of the KV’s needed serious (medium) repairs.
According to site niehorster.orbat.comat the start of the German invasion the 10th division had the following tanks: 181 BT-7, 30 T-26 and OT-26, 51 T-28, 38 T-34 and 63 KV for a total of 363.
The unit suffered heavy losses in the Ukraine, which according to table VI came to 100 BT-7, 24 T-26, 44 T-28, 32 T-34, 56 KV for a total of 256 vehicles. Basically the unit was demolished.The report is useful because it gives information on the reliability and combat performance of Soviet tanks, especially the new KV and T-34 types.
Let’s have a look at parts of the report that I found especially interesting:TECHNICAL REPORT FROM THE 10th TANK DIVISION, AUGUST 1941
[The original Russian transcript came to me from Mr. Charles Sharp. It is a report signed by the commander of the 10th Tank Division, dated 2 August 1941.) III. Equipment Performance
During the fighting every vehicle accrued at least 135 engine hours, and from 22 June through 9 July 1941 wheeled vehicles traveled approximately 300 km. From the beginning of combat operations until 2-3 July each combat vehicle was operating an average of 10 to 13 hours each day, and during this time the situation was such that there was no opportunity to carry out the appropriate mechanical inspections, which could not but affect vehicular performance. The operating conditions for the vehicles were unbelievably severe. The terrain itself where the tanks were operating was broken, marshy in some places and sandy in others. Most of the bridges were able to support light vehicles. Vehicular loads were excessive since missions, as a rule, were drawn up without considering the mechanical state of the machines. Movements were sometimes up to 200 km a day—for example, those to Volochissk, Proskurov, and the Ulanov area (Petrikovtsy). IV. Characteristics of the KV and T-34 Tanks
KV and T-34 tanks basically possessed high combat qualities: strong armor and good armament. On the battlefield KV tanks smashed enemy armor and in every instance their tanks retreated. The division’s soldiers and commanders spoke of their tanks as very reliable machines. But along with these qualities they had the following defects:
1) For the KV tanks: a) Under the impact of shells and large-caliber bullets, the turret ring and armored cupolas can jam.
b) The diesel engine has little reserve power, resulting in it being overloaded and overheating. c) The main and side clutches break down.
2. For the T-34: a) Hull armor is penetrated at 300 to 400 meters by a 37-mm antitank round. Side armor is penetrated by a 20-mm antitank round. When crossing ditches the low set of the vehicle causes its nose to dig in, and traction with the ground is insufficient due to the relative smoothness of the tracks.
b) With a direct hit by a shell the driver’s front hatch collapses. c) The vehicle’s treads are weak—any round takes them off.
d) The main and side clutches break down. All defects of the KV and T-34 tanks, along with recommendations, were reported in detail to the chief of the Main Automotive-Armored-Tank Directorate [nachalnik Glavnago avtobronetankovogo upravleniya], Lieutenant General of Tank Troops Fedorenko, and the chief of the Automotive-Armored-Tank Directorate of the Southwest Front, Major General of Tank Troops Morgunov.
Comment: Despite saying that ‘The division’s soldiers and commanders spoke of their tanks as very reliable machines’ the report also mentions serious problems with the engine, clutches and tracks of the T-34 and KV. Considering the distances covered and the fact that, according to the report, only limited repairs were possible this is not unexpected.
However the performance of the armor under fire is not what one would expect. In theory both tanks should have been secure from the German 37mm A/T gun and even the 50mm gun of the Panzer III at most combat ranges. Yet the report says that simple hits rendered the KV non-operational by jamming the turret ring and the T-34 is stated to be vulnerable to the 37mm at 300-400 meters. Even the lowly 20mm seems to have been capable of disabling the mythical T-34 tank! These statements may be exaggerations/mistakes or alternatively they could be proof of problems in Soviet tank construction in 1941.
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During combat operations the division’s repair resources accomplished the following:
Of these: | |||||||||
No in order | Vehicle type and model. | Number of repairs | medium | minor | |||||
1 | KV | tanks | 122 | 22 | 100 | ||||
2 | T-34 | " | 29 | 9 | 20 | ||||
3 | T-28 | " | 42 | 4 | 38 | ||||
4 | BT-7 | " | 87 | 26 | 61 | ||||
5 | T-26 | " | 21 | — | 21 | ||||
6 | Armored cars | 50 | 11 | 39 | |||||
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Of the 800 wheeled vehicles brought into the campaign there were lost: 210 in combat; 34 due to mechanical failures or lack of fuel and lubricants and then left behind with their drivers and surrounded by the enemy; 2 destroyed at a collection point for damaged machines when they could not be evacuated during the general retreat; 6 vehicles were stuck in bad terrain and impossible to evacuate; and 41 were abandoned during their units’ retreat due to mechanical failures and the impossibility of repairing them.
So from these figures, of 307 combat vehicles the division lost 153, or 50%, on the battlefield the; stuck in bad terrain—21, or 7%; destroyed at collection points for damaged vehicles—20, or 7%; and lost due to mechanical failures and the inability to repair or evacuate them—95, or 31%. Thus, almost half of the combat vehicles were put out of service as a direct result of combat, but the greater part of the second half were lost due to mechanical failures during the division’s retreat or destroyed at collection points for damaged machines.
Comment: It was to be expected that during a retreat many damaged but salvageable vehicles would be lost when the enemy overruns them. This was a common occurrence in WWII.